1. Field of the Invention
The present invention relates to a display device and a manufacturing method of the display device, and more particularly to a display device which includes thin film transistors and a manufacturing method of the display device.
2. Description of the Related Art
This type of display device is configured such that a plurality of pixels is arranged on a display part in a matrix array, each pixel row formed of these pixels is sequentially selected by turning on the thin film transistors provided to the respective pixels in response to scanning signals supplied to the thin film transistors via the gate signal line, and video signals are supplied to the respective pixels of the pixel row via a drain signal line which is connected to corresponding pixels of another pixel row in common at timing of such selection.
Further, as the thin film transistor, there has been known a so-called bottom-gate-type transistor which arranges a gate electrode below a semiconductor layer. In manufacturing such a thin film transistor, a method which is referred to as a resist reflow method may be used.
That is, a drain electrode and a source electrode are formed by patterning a conductor layer formed on the semiconductor layer and, thereafter, a photoresist film formed on upper surfaces of these electrodes is made to remain, and the photoresist film is made to reflow to form a photoresist film (a modified photoresist film) which constitutes a mask for selectively etching the semiconductor layer.
By using such a method, in forming the mask for selectively etching the semiconductor layer, the number of use of photolithography technique can be omitted by one time and hence, the number of manufacturing steps can be decreased.
The detail of the method is disclosed in patent document 1 (JP-A-2002-83765), for example.